One interval sets the charge
Your meter averages demand over 15-minute intervals. The highest single interval in the billing cycle becomes your billed demand. Nothing else in the month lowers it.
On a business electric bill, one 15-minute window can cost more than an entire weekend of usage. This calculator shows what your peak demand is actually costing you, and what it would save you to shave it.
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Overview
Residential customers pay for energy: kilowatt-hours, the total volume of electricity consumed. Commercial customers past a certain size pay for two things, volume and speed.
Demand, measured in kilowatts (kW), is the rate at which your facility draws power. Your meter records it as a rolling 15-minute average, and your delivery utility bills you on the single highest reading of the month. Turn on the rooftop units, the compressor, the oven bank and the lighting circuits within the same quarter hour and you set a peak that follows you onto the bill, no matter how quiet the other 2,900 intervals were.
The logic is infrastructure, not consumption. The poles, wires and transformers serving your building have to be sized for the worst moment you will ever ask of them. Demand charges recover the cost of that capacity. That is also why they are unavoidable through shopping alone: the demand charge is set by your Transmission & Distribution Utility under a PUCT-approved tariff and passes through at cost, identical no matter which retail provider bills you. Only the supply half is competitive, which is where commercial electricity rates in Texas actually differ between providers.
What you can change is the peak itself. That is what the calculator below is for. If you already know your demand charge and want to model reducing it, the peak shaving calculator handles that side.
The short version
How demand billing works in Texas, at a glance.
Your meter averages demand over 15-minute intervals. The highest single interval in the billing cycle becomes your billed demand. Nothing else in the month lowers it.
Above roughly 10 kW of recorded demand (5 kW in TNMP territory), you move onto a demand-billed rate schedule. The per-kWh delivery rate drops sharply and the kW charge takes over.
Texas TDU distribution demand charges run about $10.10 to $14.87 per billing kW depending on territory. A 60 kW peak is $600 to $890 a month before a single kilowatt-hour is priced.
Most tariffs bill the greater of this month's demand or 80% of your highest demand in the prior 11 months. One August spike can raise your floor through the following July.
Run the numbers
Pull the four numbers off a recent bill: usage in kWh, peak demand in kW, your energy rate, and your utility. Everything else is pre-filled with current tariff rates.
Set by your address, not your provider. Check the delivery section of your bill.
Listed as "Demand", "Billed kW" or "Peak kW".
Supply only. Do not include delivery charges here.
Changing the utility resets the demand charge to that tariff's current rate. Override it here if your bill differs or you carry a 4CP transmission charge.
Estimated monthly bill
$0
??"
| Energy supply | $0 |
|---|---|
| Demand charge | $0 |
| Delivery, per kWh | $0 |
| Fixed customer charge | $0 |
| Total | $0 |
Where the money goes
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Estimates use PUCT-approved TDU delivery tariffs and exclude sales tax, gross receipts reimbursement, and provider-specific fees such as base charges or minimum-usage credits. Delivery rates are revised each March 1 and September 1.
How the number is built
Four rules turn a moment of usage into a line item. In order of how they apply.
Interval meters record consumption every 15 minutes and convert it to an average kW. A 20 kW load running the full interval and a 40 kW load running half of it both register 20 kW. The highest of roughly 2,900 monthly intervals is your recorded demand, and the utility keeps it.
Billing demand is usually the greater of this month's recorded demand or 80% of the highest demand in the preceding 11 months. In February your building might genuinely need 30 kW, but if last August hit 95 kW you are billed on 76. The infrastructure stayed sized for August.
Transmission cost for larger accounts is allocated by 4CP: your average demand during the four 15-minute intervals when the entire ERCOT grid peaked, one in each of June, July, August and September. Those four windows, usually late weekday afternoons, set a transmission charge that applies for the following calendar year. Facilities that can curtail on forecasted 4CP days save on a scale nothing else on the bill matches.
Load factor is your average demand divided by your peak demand: kWh ÷ (peak kW ?- hours). A data closet running flat at 90% load factor spreads its demand charge across enormous usage and barely notices. A welding shop at 15% pays for capacity it uses in bursts. Same $/kW, very different effective rate.
What actually moves the number
Ranked by how much they typically return for what they cost.
The most common avoidable peak is everything switching on at 7:00 a.m. Sequencing rooftop units, compressors, ovens and lighting over 45 minutes costs nothing and frequently cuts the monthly peak by 10% to 20%.
Most interval data is available through Smart Meter Texas. A threshold alert during the interval, rather than a surprise on the bill, is what makes every other tactic on this list actionable.
Kilns, chargers, pumps, laundry, air compressors filling receivers. Anything that can run at 9:00 p.m. instead of 2:00 p.m. removes itself from the peak interval entirely without reducing total usage.
Motor-heavy facilities with lagging power factor get billed on kVA or face a penalty adjustment. Capacitor banks typically pay back inside two years when the penalty is already showing on the bill.
Battery systems discharge into the peak interval and recharge overnight, clipping the top of the curve. In 4CP-exposed accounts, curtailment on forecasted grid-peak days can be worth more than the demand charge itself.
Demand charges pass through at cost, but supply is competitive. A load-factor-aware quote from a provider that has seen your interval data usually beats a rate quoted off usage alone. Our commercial electricity shopping guide covers what to ask for.
Reading the bill
The vocabulary that shows up in the delivery section of a commercial invoice.
A rate of power, how hard you are pulling at a given moment. Demand charges are priced in dollars per kW per month.
A quantity of energy, one kW sustained for one hour. Energy charges are priced in cents per kWh.
Your own highest 15-minute demand, whenever it happened. Distribution demand charges are billed on NCP.
Your demand during the four monthly intervals when all of ERCOT peaked, June through September. Sets transmission cost for the next year.
The rider your TDU uses to recover transmission investment between rate cases. A large driver of recent delivery increases.
The ratio of working power to total power drawn. Below roughly 0.95, motor-heavy sites are billed on kVA or assessed an adjustment.
Next step
The delivery half of your bill is fixed by tariff. The supply half is not.
Two businesses on the same street with the same peak demand pay the same demand charge and can pay very different energy rates. Once you know your load factor from the calculator above, you have the number that determines whether a quote is competitive for your shape of usage.
Common questions
Demand charges on Texas commercial electricity bills.
A demand charge bills you for the rate at which you draw power, measured in kilowatts, rather than the total energy you consume. Your meter records demand as a rolling 15-minute average and your delivery utility bills the single highest reading of the month. It covers the cost of sizing poles, wires and transformers for the largest load your building will ever place on them.
In most Texas TDU territories, recorded demand above 10 kW moves you onto a demand-billed rate schedule. TNMP sets that threshold at 5 kW. Below the threshold the utility recovers its cost through a higher per-kWh delivery rate instead, which is why crossing the line sometimes lowers the total bill rather than raising it.
Distribution demand charges run roughly $10.10 to $14.87 per billing kW per month depending on the utility, based on tariffs effective March 1, 2026. CenterPoint is at the low end and TNMP at the high end. A 60 kW peak therefore carries about $600 to $890 a month before any energy is priced. Rates are revised each March 1 and September 1.
A ratchet sets a floor under your billing demand. Most Texas tariffs bill the greater of the current month's recorded demand or 80% of the highest demand in the preceding eleven months. A single August peak of 95 kW can therefore set a 76 kW floor that applies through the following July, even in months when the building genuinely needs far less.
No. Demand charges are set by your Transmission and Distribution Utility under a PUCT-approved tariff and pass through at cost, identical no matter which retail provider bills you. Switching providers changes the supply portion of the bill only. Lowering the demand charge requires lowering the peak itself.
4CP, or four coincident peaks, allocates transmission cost based on your demand during the four 15-minute intervals when the entire ERCOT grid peaked, one each in June, July, August and September. It generally applies to larger accounts and sets a transmission charge for the following calendar year. It is separate from the distribution demand charge, which follows your own peak whenever it happens.
Load factor is average demand divided by peak demand, calculated as kWh divided by peak kW times hours in the period. A facility running flat at 80% load factor spreads its demand charge across heavy usage and barely feels it. A facility at 15% pays for capacity it uses in short bursts, which produces a much higher effective cents-per-kWh rate on the same tariff.